As well known, charcoal roast boards currently used in restaurants and the like simply comprise circular or rectangular grills. When such a conventional grill is used as a charcoal roast board, exchange of roast boards should be performed typically about 3 or 4 times to prevent meat from being burned. Thus, there is inconvenience in use due to the frequent exchange of conventional charcoal roast boards, and there is also a risk of the occurrence of a safety accident upon exchange of roast boards by a service worker. Further, there are many problems of customers dissatisfaction caused due to delayed exchange of charcoal roast boards, and increased personnel expenses due to an increase in the number of service workers, and the like.
Moreover, when the charcoal roast boards are washed, additional service workers manually wash them one by one. This causes a problem of increased management costs that result from increased personnel expenses, increased working time due to difficulty in washing the charcoal roast boards, and the like.